System for converting electrical energy supplied by a network and a conversion method implemented by means of such a conversion system

Abstract

This system for converting the electrical energy delivered by a supply network comprises of: a converter and at least one zero-sequence current limiting stage flowing in the converter. The or each limiting stage comprises an active compensation circuit comprising a magnetic component and a voltage source connected to the magnetic component, the voltage source and the magnetic component being adapted to serially inject with the converter an active compensation voltage of the zero-sequence voltages generated by the converter.

Description

BACKGROUND TO THE INVENTION[0001]In electrotechnical systems supplied from power systems using voltage inverters, zero-sequence currents are generated due to the control strategy of the inverters, which induce common-mode disturbances in the systems, in particular overvoltages in the machines, electrical disturbances, electromagnetic disturbances limiting the electromagnetic compatibility (EMC) of the devices, disturbances in the supply network, in the context of a system directly connected without a transformer between the network and the system, etc.[0002]These zero-sequence currents flow in the first place toward the ground, flowing in a loop passing through the voltage inverters, the parasitic capacitances of the system, such as the parasitic capacitances of the rotating machines and / or the cables, and the ground.[0003]Limiting the zero-sequence currents may be modified by the regulation of the converter by prohibiting certain switching states. Zero-sequence currents are further...

AI Technical Summary

Benefits of technology

[0018]An aspect of embodiments of the invention is therefore to overcome the above-mentioned various disadvantages and to propose a system for supplying an AC load capable of eliminating the different types of zero-sequence currents likely to flow through the supply system regardless of its configuration.

Problems solved by technology

Although the above referenced solution is advantageous in many respects, it does not make it possible to compensate for various types of zero-sequence flow currents and only allows the compensation of the zero-sequence current flowing to the ground, according to a loop passing through the voltage inverters and the parasitic capacitances of the system.

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